A sea of scales in a rainbow of colors surrounded the stage; a dashing blue dragon standing upon the stage riled the crowd with his theatrics. "And now, if you please, a volunteer!" He wheeled across the stage, floating just a measure above the floor beneath him, reaching out as if to snatch one of them from the crowd. He settled on a red dragon who was all too excited to participate in the spectacle; with a swish of his tail, magic lifted the red into the air, and both dragons settled onto the stage. "Tell me, my friend, what is your name?" The red nervously responded, "P-Pillin! I've been watching your magic since before my first hibernation, Oilos!" Oilos laughed. "Wonderful, my dear Pillin, wonderful! Then I suspect you know what's going to happen next! It's always good to have a seasoned assistant! Please, everyone, give Pillin an encouraging cheer!" The crowd went wild; Pillin shuffled her wings, embarrassed.
"It was the first time I had actually met Oilos; I was so enamored with him. It's hard to believe I was ever like that; but I guess anything can change, given a couple thousand years." Pillin sighed. "Standing there on the stage next to him, though, I could feel a certain...malice. I'm not sure if I imagined it, but something about the way he looked me in the eye said, 'Don't screw this up, or I'll make you pay.' Suddenly, I wished I hadn't volunteered. I never went to another one of his performances after that."
A pink kobold stood listening to the voice on the intercom, transfixed. She could only hear Pillin's voice, but found herself staring at the speaker as if she was looking directly at Pillin. Iora shook herself loose and continued down the hall to which she had been directed. "So the ultimate evil, sealed away in this facility, was once...A performance magician?"
Pillin chuckled over the intercom. "Looking back, he was more of a con man than performance artist. He could do the magic, and his present form is proof of that; but back then it was all about charming money out of his adoring fans."
Iora grimaced. "And I'm guessing at some point it stopped being money but their literal life force he was charming out of them?"
The intercom was silent for a moment. "...I think that was always his goal. It could've been happening the whole time; there were certainly unexplained disappearances, but it's hard to say anything definitive. All I know is that, at some point, he found a path to immortality. His following already had an almost cult-like fanaticism to it, but it suddenly rose to a fever-pitch. Then, he put on his biggest show; it'd be the last show he did, and the last show any of the audience ever saw. Two hundred fifty thousand attendees was apparently the first step, and they vanished in an instant." Iora shivered. The intercom was silent for a long time.
"So...then this place was constructed?" Iora asked, breaking the silence. Pillin seemed remorseful as she spoke. "No. We didn't realize what he had done at the time, so we treated it like any other incident. Sure, we investigated the magic he used, but he was a performance magician; sleight of hand and misdirection were his specialty. He laughed as we executed him, promised that it was only the beginning."
Iora pondered for a moment. "You talk like you were there for the execution." Iora had come to a locked door, and stood waiting for Pillin to unlock it. The intercom remained silent; Iora assumed Pillin was manipulating the security system to open the door for her, but the absence of her voice in the otherwise empty facility made Iora uncomfortable.
Pillin resumed her story over the intercom as soon as the lock on the door clicked open. "Dying, apparently, was the next step. We had no clue. We didn't know what he was up to, and we didn't know what he would become. He was just an unstable dragon that had committed an unspeakable atrocity."
Iora nodded. "What was the first sign that Oilos wasn't gone?"
Pillin sighed. "Well, we knew something was weird as soon as the execution took place. Death is an extremely simple spell; you cast it, and it stops all the electrical activity in a being. When we cast it on Oilos, his body crystallized...and the casters died."
Iora's skin began to crawl. "Crystallized?"
Iora began to connect the dots, and Pillin gave voice to the Kobold's fear. "It was like nothing we'd ever encountered before; we took to calling it Mage-rot. It wasn't a thing before Oilos; a new principle of magic, powered by the souls of Oilos's last show, fueling his immortality. Once upon a time when you used too much magic your body would simply burn up; now, you become a part of him. So long as there's a speck of that dust in the world, he can eventually pull together a functional body."
Iora grimaced. "What, exactly, did this crystallization look like?"
Pillin's alarm was apparent through the intercom. "That's a scary question to ask. The body sort've disintegrates into dust." Iora remained silent; Pillin inferred her meaning, and panic began to creep in. "You've seen it? That shouldn't be possible!
Iora shook her head. "I can't say for sure, but that's why I'm here."